Apparatus for satinizing fibrous webs

ABSTRACT

1. A calendar for satinizing fibrous webs directly with only two roller pairs arranged in a plane above each other in vertical alignment, comprising: a first metallic satinizing roll, having a relatively hard rough surface for satinizing; a first backup roll in first nip defining relationship with only said first metallic satinizing roll, having a resilient smooth surface comprising a synthetic material formed by polymerization of one or more materials; a second metallic satinizing roll; having a relatively hard rough surface for satinizing; a second backup roll in second nip defining relationship with only said second metallic satinizing roll, having a resilient smooth surface comprising a synthetic material formed by polymerization of one or more materials, and fibrous web support means for continued feeding of said web first through said first nip in one direction of entry, said first and second metallic satinizing rollers having uppermost and lowermost locations remote from each other and said first and second backup rollers directly adjoining each other in location intermediate said first and second metallic satinizing rolls with looping angle amounting to 180 degree around one backup roll resulting in web exit in direction substantially opposite to direction of entry and alternately for continued feeding of said web in just the opposite way.

06L 1974 J. SCHLUNKE 3,841,963 I APPARATUS FOR SATINIZING FIBROUS WEBSFile d lay s, 1973 United States Patent US. Cl. 162-362 9 ClaimsABSTRACT OF THE DISCLOSURE An apparatus for satinizing fibrous websincluding a first satinizing roll having a relatively hard and roughsurface and a first backup roll in first nip defining relationship withthe first satinizing roll and having a resilient smooth surface. Inaddition, a second satinizing roll and a second backup roll for a secondnip is employed. Web feeding rolls are positioned to feed a web firstthrough the first nip and thereafter through the second nip whereby theweb is satinized.

This is a continuation-in-part of application of copending Ser. No.160,217, filed July 6, 1971, now abandoned, which was a streamlinecontinuation of original application Ser. No. 878,772, filed Nov. 21,1969, now abandoned, both belonging to the assignee of the presentinvention and predecessors thereof.

BACKGROUND OF THE INVENTION The present invention relates to asatinizing device, such as a paper calender, wherein sized papers suchas those used in the printing and related processes so that a dulleffect on the paper is produced. Such a dull effect on the paperimproves the quality and pictorial effect of the printing when comparedwith high gloss papers.

The prior art attempts to achieve the dull surface on paper was firstcentered about a process wherein the web was passed between two paperrolls. Because the rolls very rapidly became smooth and hard and thuslost the dulling effect, these paper rolls were reroughened by havingcast metal rolls being pressed against them. Eventually, the prior artresorted to the production of dulled paper and other webs by directpressure of a roughened cast or steel roll against the paper web.

None of these processes achieved a great degree of commercial successbecause of the deficiencies with which they are afliicted. Rough paperrolls form an abrasion which quickly deteriorates the paper shell due tothe constant reabrasion. Large quantities of dust must be collected andremoved, which presents a substantial problem for that type of a device.The same phenomenon also occurs with calenders where the dulling isaccomplished by cast or steel rolls, and this occurs at the roll endsnot covered by the paper web. It has also been found that in the case oftwo sided dulling, where the material web must discharge between tworelatively elastic rolls, the dulling embossed by the metal rolls iseliminated partially, and due to the nonhomogeneous nature of paperrolls, an irregular glossy effect or marble effect is noted. It hasgenerally been found to be impossible to simultaneously achieve anadequate dulling effect while also maintaining the smoothness anduniform paper thickness and other qualities which is necessary inquality printing.

Accordingly, it is an object of this invention to provide a device whichis satisfactory for satinizing or dulling the surface of paper and otherwebs to permit the creation of uniformly dull paper which is yet smoothand uniform in quality.

It has now been discovered that a proper apparatus for satinizingfibrous webs may be provided. Basically, this device includes a firstsatinizing roll, having a relatively hard rough surface. In a first nipdefining relationship with this first satinizing roll is a first backuproll which has a resilient smooth surface. A second satinizing roll anda second backup roll form a second nip in the same manner. The webfeeding means is adapted to feed the web first through the first nip andthereafter through the second nip. In this manner, the web is properlysatinized without material effects on the uniformity, smoothness, andother properties of the paper. The satinizing rolls are metal or steelrolls and are provided with a dull embossing and the paper guide is suchthat the steel rollers directly emboss the dulling upon the paper web.Although even in this arrangement with bilateral embossing the paper webprovided with the dulling must discharge between both plastic rollers,that is the two dulled surfaces again are pressed somewhat, thesurprising discovery has been made that neither is the dulling dispersedwith glossy spots nor does an abrasion form on the ends of the plasticrolls not covered by paper. Undoubtedly, this is caused by the fact thatthe plastic rolls do not become inhomogeneous despite the steadycompression in the roller joint, and that the high elasticity of theplastic does not permit a formation of abrasion at the exposed ends ofthe rollers.

In a preferred embodiment, the web feeding means is adapted to feed theweb first through the first nip such that one side of the web contactsthe satinizing roll. Thereafter, the web feeding means passes the webthrough the second nip such that the other side of the web contacts thesatinizing roll. In this manner, both sides of the paper may be treated.In addition, it is also possible according to the present invention todefine a third nip between the first and second backup roll, whereby thefeeding means is adapted to feed the web through the third nip afterpassage through each of the first two hips, to render uniformity to theresulting paper product. It should also be noted that the dulling orsatinizing of the top side of the paper web or first satinized side isneutralized slightly since it is pressed during the passage the devicetwice by the elastic roll, while the bottom side is pressed only once.Accordingly, it is a preferred embodiment to provide a first satinizingroll having a sightly more rough surface than the second satinizingroll.

In another embodiment in which all rolls are located one upon anotherthere is noted that at least the rolls are capable of being pressedagainst each other through pressure means exerting force from above inalignment with the axes of the rolls that are in parallel and arrangedone above the other in vertical positioning of horizontally extendingrolls. Thus, both synthetic material rolls together press upon the webpassing through the nip that is considerably more narrow and closertogether than that of the previous embodiments. Thereby, the rolls aremore effective in exerting a smoothening effect upon the web. Thisprovides an additional option and possibility of either using thearrangement for additional smoothening or only using the arrangement ofrolls and not the pressure means without any supplemental smoothening inthe nip.

For a more complete understanding of the present invention, reference ishereby made to the drawings, in which:

FIG. 1 is a schematic illustration showing one embodiment of the presentinvention, and;

FIG. 2 is a schematic drawing showing the surface of the firstsatinizing roll having a slightly more rough surface than the secondsatinizing roll;

FIG. 3 is a schematic drawing showing the surface of the secondsatinizing roll.

As shown in FIG. 1, a web passes between a first satinizing roll 12 anda first backup roll 14. The satiuizing roll 12 has a relatively hardrough surface and may be prepared from most metals, and preferably fromiron or steel. The rough surface may be achieved in a number of ways,such as by sanding or etching, while a preferred method to provide therough surface is to subject the surface to the conventional dull chromeplating process.

The backup roll 14 has a resilient smooth surface and may bemanufactured from plastics, or other materials which are capable ofbeing formed into resilient smooth surfaces. The term plastic isintended to mean those synthetic materials which are formed bypolymerization of one or more materials to form either a thermoplasticor thermosetting material.

After the web 10 has passed through the nip 13 defined by the satinizingroll 12 and the backup roll 14, it is guided by web guide means aroundrolls 19 and 21 to a point where it wraps second satinizing roll 18. Thesecond satinizing nip 17 is formed between the satinizing roll 18 andthe backup roll 16. It will be noted from FIG. 1 that the one side ofthe web is treated at nip 13 while the other side of the nip receives asatinizing effect to nip 17. Finally, a Web 10 passes through a hip 15which is formed by the two backup rolls 16 and 14 to insure uniformityof the paper smoothness and thickness.

The first and second backup rollers 14, 16 respectively directly adjoineach other in location intermediate the first and second metallicsatinizing rolls 12, 18 with a looping angle amounting to 180 around onebackup roll 16 resulting in web exit in a direction substantiallyopposite to direction of entry thereof.

In this embodiment all rolls are located one upon another and at leastthe rolls are capable of being pressed against each other throughpressure means exerting force from above in alignment with the axes ofthe rolls that are in parallel and arranged one above the other invertical positioning of horizontally extending rolls. As illustrated,the bearing means of the uppermost satinizing roll 12 at oppositejournalling ends thereof can be subjected respectively to hydraulicpressure exerted by a piston P having a rod H reciprocable with respectto a cylinder C representing pressure means to which fluid underpressure from a source S is supplied to a chamber above the piston P.The pressure means can be arranged to exert force on each side as to thebearing or journalling means for the rotational axis of the uppermostsatinizing roll 12 of hard metal with a rough surface as describedpreviously. In addition, the rolls with their own weight engage uponeach other and/ or additionally the hydraulic or fluid pressure appliedto the piston P can maintain such continuous pressure for engagementcontinuously in close relationship as to the four rolls stacked oneabove the other. Thus, both synthetic material rolls 14 and 16 togetherpress upon said web 10 passing through the nip 15 that is considerablymore narrow and closer together than that of the previous embodiments.Thereby, the rolls 14 and 16 are more effective in exerting asmoothening effect upon the web 10. This provides an additional optionand possibility of either using the arrangement of FIG. 1 for additionalsmoothening or only using the arrangement of rolls shown in FIG. 1 andnot the pressure means without any supplemental smoothening inthesmaller gap 15. The piston P can have a spring around the rod (notshown) or a valve-controlled inlet can be added to communicate with thechamber around the rod R below the piston P so that selective actuationof the piston P and cylinder C can occur for movement of the rolls 12,14, 16 closer together or farther away from each other as illustrated byFIGS. 1 and 3 respectively. A suitable frame F can be provided formounting and journalling the rolls as well as the piston and cylinderpressure means.

Also shown in FIG. 1 are cool air ducts 22 and 23 which are provided tomaintain a working temperature of the backup rolls 14 and 16 less thanthat which may permit alteration of the paper surface. Preferably, theoperating conditions of all of the rolls should be maintained at lessthan F.

Also additional cooling means for the satinizing rolls 12, 18 areprovided. An inlet 30 permits circulation of a cooling fluid in the roll18. Withdrawal of the fluid in the roll 18 through line 32 in aconventional manner permits recirculation to maintain the desiredtemperature.

In case of bilateral dulling according to FIG. 1 the paper web 10 firstreaches the gap between rolls 12 and 14, is thereby embossed dull andthen, via both reversing rolls 19, 21 and after moving around the lowermetal roll 18 it is dulled in the gap between rolls 16 and 18 by theembossing roll 18 on the reverse side, then moves around the roll 16 andleaves the calender via the gap between both elastic rolls. The dullingembossed on is thereby not eliminated by the two elastic rolls, but ismerely blunted slightly and stabilized. It has been discovered, however,that the dulling of the top side of the paper web is blunted slightlymore, as it is pressed during the passage twice by the elastic roll,while the bottom side is pressed once, in the gap between rolls 18 and16.

Further according to the present disclosure, this disadvantage isobviated in that the metal roller has a slightly greater dulling thanthe metal roller 18.

In contrast to prior art, where duiling of the metal rollers wasaccomplished by sanding or etching, an even finer structure is needednow which is produced by different degrees of dull chrome plating.

The peculiarity of the plastic rolls makes it possible to apply higherline pressures of about 300 kg./cm. and to achieve thus besides dullingalso a high smoothness. Because considerable amounts of heat aregenerated during the passage through the calender due to the deformationof the paper, particularly by the deformation work of the plastic rolls,while elevated temperatures can modify the sizing substance chemically,it is proposed, further according to the invention, to so cool all rollsthat a maximum operating temperature of about 35 C. is not exceeded. Thecooling is accomplished in the steel rolls from the interior by acoolant circulating in the roller perforation, while in the plasticrolls it is accomplished by blowing on cooling air which is expelleduniformly from nozzle bodies 22, 23 and aspirated away if necessary bysuction openings located between the nozzles.

A particular advantage of the invention consists in that withoutmodification of the chemical sizing recipe the same paper can be dulledoptionally or be refined to high luster on a standard satinizingcalender.

Naturally, it is within the scope of the invention to form the calenderin a single-purpose design only for unilateral dulling merely from rolls12 and 14.

In summary, there is provided a calender for satinizing fibrous webswith only two roller pairs arranged in a plane above each other invertical alignment. The foregoing includes a first metallic satinizingroll, having a relatively hard rough surface; there is provided a firstbackup roll in first nip defining relationship with only said firstmetallic satinizing roll, having a resilient smooth surface comprising asynthetic material formed by polymerization of one or more materials.There is provided a second metallic satinizing roll, having a relativelyhard rough surface; provided therewith is a second backup roll in secondnip defining relationship with only said second metallic satinizingroll, having a resilient smooth surface comprising a synthetic materialformed by polymerization of one or more materials. The foregoing alsocomprises fibrous web support means for continued feeding of said webfirst through said first nip in one direction of entry and thereafterthrough said second nip in substantially the same direction of entry,said first and second metallic satinizing rollers having uppermost andlowermost locations remote from each other; the first and second backuprollers directly adjoining each other in location intermediate saidfirst and second metallic satinizing rolls with looping angle amountingto 180 around one backup roll resulting in web exit in directionsubstantially opposite to direction of entry.

The foregoing features provide a decisive difference of making itpossible to get along with an essentially smaller number of rollerswithout hereby in any way involving the goal or object in a lesseffective manner. In spite of the essentially smaller number of rollers,there is attained the object to roughen or emboss both sides of thepaper surface. With the roller paper consisting of one metallicroughening or embossing roller and one roller covered with syntheticmaterial, the roller covered with synthetic material is less stiff inand of itself and thus can encounter greater than the metallicroughening or embossing roller.

Further a roughening or embossing roller never works directly togetherwith a roller covered with synthetic material covering withoutpositioning therebetween a paper track so that the dust-type wear orrubbing off of the synthetic material roller does not become securelydeposited only in the roughening or embossing depressions respectivelyelevations of the roughening or embossing roller, but rather also nopowder or dust quantity becomes generated which deposits itself upon themachine parts and which would form residue or deposits upon the papertrack. Otherwise, there results a wash-out or blurred roughening orembossing, prematurely strong wear of synthetic material covering anddust or powder crusts upon the calender or glazing rollers.

There arises neither a bending through nor drooping of rollers coveredwith synthetic material nor does there arise any direct operation of aroller covered with synthetic material with respect to the upper surfaceof a roughening or embossing roller.

For solution of the goal to carry out the roughening or embossing uponboth outer surfaces of the paper track, there are different featuresutilized which are subject to limitation or restriction to the sampleembodiment according to FIG. 1 of the patent drawings. These differentfeatures include the following:

(1) There are only two roller pairs arranged in a plane above each otherand consisting respectively of a metallic roughening or embossing rollerand a roller with a synthetic material covering whereby the producttrack or path is carried out respectively between only one roughening orembossing roller and only one roller having a synthetic materialcovering.

(2) Both roughening or embossing rollers form the upper and lower rollermeans.

(3) The paper track is introduced at a time in the same direction intothe roller gap between the roughening or embossing roller and the rollerwith synthetic material covering.

(4) The angle of grip or looping angle of the one roller covered withsynthetic material amounts to 180.

Rollers with covering of synthetic material subject to intermediatepositioning of the paper track engage against each other respectively.As indicated by FIG. 1 of the drawings, the product track or paper isintroduced from the right toward the left between the rollers 14 and 12and thereafter the same comes again between the rollers 16 and 18 in thesame direction, respectively after looping or winding around the rolls19, 21.

The product track or paper also can travel in opposite runningdirection. The same can next be introduced into the gap between therollers 14 and 16 in order then to come into the roller gap between therollers 16 and 18 of the roller gap between the rollers 14 and 12. Alsoin this case the running direction of the product track or paper betweenthe embossing or roughening rollers and the pertaining roller meanscovered with synthetic material again is the same. The previouslydescribed track guidance with rollers 14 and 16 engaging against eachother has the advantage that subsequently unembossed or unroughenedproduct track is guided between the rollers 14 and 16 and hereby noroughening or embossing is made smooth. (Compare opposite runningdirection of the product track according to FIG. 1.)

Both embossing or satinizing rollers are to have different embossing orsatinizing depth. There is neither different roller diameter norembossing or satinizing rollers to begin with but rather there isprovided a different embossing or satinizing depth per se without anydifference in pressure.

Substance of the elastic synthetic material rollers rests upon Polyamideas a basis. For instance, an elastic material such as Nylon would beamong substances suitable for use in this location.

The foregoing in summary concerns a calender for mat or dull satinizingof paper paths consisting of two steel rollers located outwardly andvertically one above the other with dull or mat ridges and two elasticrollers arranged therebetween. This calender is characterized by way ofunification of the following features in combination with each other:

(A) The elastic rollers 14 and 16 consist of synthetic material;

(B) The upwardly located steel roller 12 has a more coarse mat ridgemeans than the steel roller 18 located below;

(C) The paper path or web 10 after passage and guidance between the onemetal roller 12 and the elastic roller 14 arranged therewith caused tobe guided around the second metal roller 18 and around the secondelastic roller 16.

One of the features of the present invention is that high nip pressuresin excess of 300 kg./cm. may be achieved, thereby not only providing adulled finish but a high smoothness and uniform caliper.

It is, of course, to be understood that the present invention, is, by nomeans, limited to the particular construction shown in the drawings butalso comprises any modifications within the scope of the appendedclaims.

What I claim is:

1. A calender for satinizing fibrous webs directly with only two rollerpairs arranged in a plane above each other in vertical alignment,comprising:

a first metallic satinizing roll, having a relatively hard rough surfacefor satinizing;

a first backup roll in first nip defining relationship with only saidfirst metallic satinizing roll, having a resilient smooth surfacecomprising a synthetic material formed by polymerization of one or morematerials;

a second metallic satinizing roll; having a relatively hard roughsurface for satinizing;

a second backup roll in second nip defining relationship with only saidsecond metallic satinizing roll, having a resilient smooth surfacecomprising a synthetic material formed by polymerization of one or morematerials, and

fibrous web support means for continued feeding of said web firstthrough said first nip in one direction of entry and thereafter throughsaid second nip in substantially the same direction of entry, said firstand second metallic satinizing rollers having uppermost and lowermostlocations remote from each other and said first and second backuprollers directly adjoining each other in location intermedaite saidfirst and second metallic satinizing rolls with looping angle amountingto around one backup roll resulting in web exit in directionsubstantially opposite to direction of entry and alternately forcontinued feeding of said web in just the opposite way.

2. The apparatus of claim 1 wherein said first and second backup rollsare further positioned to define a third nip therebetwen, and said webpasses through said third nip after passage of said web through saidsecond nip.

3. The apparatus of claim 2 wherein pressure means are provided to exerta force to increase pressure between the first and second backup roilsthereby to add smoothing eflect upon the web passing in engagementbetween said backup rolls.

4. The apparatus of claim 1 wherein cooling means are provided to lowerthe operating temperature of each of said metallic satinizing rolls toless than 100 F.

5. The apparatus of claim 4 wherein with said vertically aligned rollssaid nip pressure at each nip is in excess of 300 kg./cm., made possibleby the weight of the metallic satinizing rolls and the cooling means.

6. The apparatus of claim 1 wherein cooling means are provided to lowerthe operating temperature of each of said backup rolls respectively toless than 100 F.

7. The apparatus of claim 1 wherein said satinizing rolls having ametallic surface having a fine dull embossing depth finish.

8. The apparatus of claim 1 wherein said backup rolls having a resilientsmooth surface formed from a plastic.

9. The apparatus of claim 1 wherein satinizing depth diifers becausesaid first satinizing roll has a slightly more rough surface than saidsecond satinizing roll.

References Cited UNITED STATES PATENTS p S. LEON BASHORE, PrimaryExaminer R. H. TUSHIN, Assistant Examiner US. Cl. X.R.

1. A calendar for satinizing fibrous webs directly with only two rollerpairs arranged in a plane above each other in vertical alignment,comprising: a first metallic satinizing roll, having a relatively hardrough surface for satinizing; a first backup roll in first nip definingrelationship with only said first metallic satinizing roll, having aresilient smooth surface comprising a synthetic material formed bypolymerization of one or more materials; a second metallic satinizingroll; having a relatively hard rough surface for satinizing; a secondbackup roll in second nip defining relationship with only said secondmetallic satinizing roll, having a resilient smooth surface comprising asynthetic material formed by polymerization of one or more materials,and fibrous web support means for continued feeding of said web firstthrough said first nip in one direction of entry, said first and secondmetallic satinizing rollers having uppermost and lowermost locationsremote from each other and said first and second backup rollers directlyadjoining each other in location intermediate said first and secondmetallic satinizing rolls with looping angle amounting to 180 degreearound one backup roll resulting in web exit in direction substantiallyopposite to direction of entry and alternately for continued feeding ofsaid web in just the opposite way.